A method for manufacturing a conventional module component having an electrical shield is shown in FIG. 14. First, substrate 1 is mounted with mounting components 3 (S141), and then covered with sealing member 4 made of resin (S142). Substrate 1 covered with sealing member 4 is then provided with dividing groove 6 to divide mounting components 3 into desired circuit blocks (S143). Sealing member 4 and dividing groove 6 are coated with metal film 2 on their surfaces by plating or the like (S144) so as to obtain the module component. Metal film 2 has an electrical shielding effect by being connected with ground pattern 5 of substrate 1 and also has the effect of shielding the circuit blocks individually. One such circuit module in which a plurality of circuit blocks are shielded individually is disclosed in Japanese Patent Unexamined Publication No. 11-150391.
However, the conventional electrical shield structure must have dividing groove 6 to divide substrate 1 into desired circuit blocks so as to make metal film 2 and ground pattern 5 electrically continuous with each other. This requires making a cut on substrate 1 as deep as to reach the second layer of ground pattern 5. The provision of this cut makes it hard to maintain the bending strength and to reduce warpage of the module component. As a result, the wiring between the circuit blocks becomes vulnerable to breakage, thereby causing defective circuit operation. To overcome this defect, dividing groove 6 can be filled with resin to prevent the module component from decreasing in strength; however, this approach requires an additional process of filling in the resin, thereby leading to cost increase.